The polymer and pharmaceutical industries frequently require difunctional acids or esters thereof. For example, difunctional monomers such as phenolic acids are used as capping agents or termonomers in polyester formation. One particular compound so utilized is p-hydroxyphenyl acetic acid. This is a particularly expensive monomer formed by a complex reaction sequence. Substituted phenol acids are also used in pharmaceuticals where benzopyran derivatives are anti-asthma drugs.
A particularly desirable product in this family of compounds is 2-methyl-2-(p-hydroxyphenyl) propionic acid, a homolog of p-hydroxyphenyl acetic acid. Synthetic routes leading to this compound involve several steps and in general, afford low to modest yields of the desired product. For example, Defensive Publication No. T908009 describes the production of this propionic acid by reacting p-quinone with dimethylketene and subsequent hydrogenation. This chemistry is extremely costly and, in fact, cost prohibitive. Other multi-step syntheses are also cost prohibitive and are described, for example, in German Offen. No. 2,537,204 (Aug. 23, 1974), Jonsson, N. A., e.t., Acta Pharm. Suec 164-167 (1974); Martin, J. C., et al. J. Org. Chem., 36 (16) 2216-22 (1971) and Jonsson, A. Acta Chem. Scand. 8, 1211 (1954).